Have you ever had a file on your computer that was so ridiculously large it was all but impossible for you to send it to a friend as an email attachment? Or, even better, have you ever wanted to email someone a BUNCH of different files at the same time but didn’t want to go through the tedious process of having to attach the files to the email one at a time? That’s where the ZIP file format comes in.

The ZIP file format allows you to both compress and archive your files. What does that mean in English? Well, ‘file compression’ is just a way of saying ‘smushing a file so that it takes up less space on your hard drive’ and ‘file archiving’ is just a way of saying ‘making a copy of the original file so that you can put a copy somewhere else.’ The file compression part of the ZIP file format is what makes it so popular with web developers. For example, in the PowerPoint Files section of my website I’ve placed about two dozen PowerPoint files you are free to download. Each of those files are “zipped” so that they take up less hard drive space and therefore will take less time for you to download.

How do you open [or “unzip”] a ZIP file? If you have Windows XP, Windows Vista, Windows 7, or Apple OS, just double-click on the zip file or folder, which will look something like this:

Notice the zipper? That’s Windows 7’s way of telling you that the file or folder has been zipped. Once you double-click on that file or folder, it should open just as if it were a regular file or folder on your computer.

What if you don’t have Windows XP, Windows Vista, Windows 7, or Apple OS? Well you need to download and install a special piece of software that will help to zip and unzip files. This may sound like more trouble than it is worth, but a zip/unzip program is an ESSENTIAL tool, especially if you are going to be using the Internet a lot.

NOTE: PC users on Windows XP, Windows Vista, Windows 7 all can unzip files natively and do NOT require a program. The video above shows you how to unzip a file on Windows XP, Windows Vista, Windows 7.

Download either program and then install it. After that, whenever you encounter a zipped file (a file that ends in “.zip”), just double-click on that file. Your unzip program will automatically open, and you can then choose where you want the unzipped version of that file to be saved on your computer.

NOTE: Sometimes a large download might become corrupted while it travels to your computer, but not to worry! Usually WINRAR will open the file just fine, even if WinZIP is showing corrupted.